TY - JOUR

T1 - Bioconversion of (+)-valencene in submerged cultures of the ascomycete Chaetomium globosum

AU - Kaspera, Rüdiger

AU - Krings, Ulrich

AU - Nanzad, Tsevegsuren

AU - Berger, Ralf G.

N1 - Funding information: This project was supported by the Federal Ministry of Education and Research (BMBF 0330062) and is part of the joint initiative project ‘Biologisch aktive Naturstoffe—Che-mische Diversität’ at the University of Hannover. We thank E. Hofer of the Department of Organic Chemistry from the University of Hannover for his help in NMR analyses

PY - 2004/12/16

Y1 - 2004/12/16

N2 - Submerged cultures of the ascomycete Chaetomium globosum oxidised the exogenous sesquiterpene (+)-valencene to nootkatone via the stereoselective generation of α-nootkatol. Inhibition experiments suggested that the first introduction of oxygen, the rate-limiting step of the bioconversion, may have been catalysed by a cytochrome-P450-monooxygenase. However, nootkatone was not the final metabolite: further flavour-active and inactive, non-volatile oxidation products were identified. (+)-Valencene and the flavour-active mono-oxyfunctionalised transformation products, α-nootkatol, nootkatone, and valencene-11,12-epoxide accumulated preferably inside the fungal cells. Di- and poly-oxygenated products, such as nootkatone-11,12-epoxide, were found solely in the culture medium, indicating an active transport of these metabolites into the extracellular compartment during (+)-valencene detoxification. These metabolic properties may have contributed to the high tolerance of the fungus towards the exogenous hydrocarbon.

AB - Submerged cultures of the ascomycete Chaetomium globosum oxidised the exogenous sesquiterpene (+)-valencene to nootkatone via the stereoselective generation of α-nootkatol. Inhibition experiments suggested that the first introduction of oxygen, the rate-limiting step of the bioconversion, may have been catalysed by a cytochrome-P450-monooxygenase. However, nootkatone was not the final metabolite: further flavour-active and inactive, non-volatile oxidation products were identified. (+)-Valencene and the flavour-active mono-oxyfunctionalised transformation products, α-nootkatol, nootkatone, and valencene-11,12-epoxide accumulated preferably inside the fungal cells. Di- and poly-oxygenated products, such as nootkatone-11,12-epoxide, were found solely in the culture medium, indicating an active transport of these metabolites into the extracellular compartment during (+)-valencene detoxification. These metabolic properties may have contributed to the high tolerance of the fungus towards the exogenous hydrocarbon.

UR - http://www.scopus.com/inward/record.url?scp=21344460013&partnerID=8YFLogxK

U2 - 10.1007/s00253-004-1794-0

DO - 10.1007/s00253-004-1794-0

M3 - Article

C2 - 15602686

AN - SCOPUS:21344460013

VL - 67

SP - 477

EP - 483

JO - Applied Microbiology and Biotechnology

JF - Applied Microbiology and Biotechnology

SN - 0175-7598

IS - 4

ER -